Defrosting timer



Jan. 2, 1951 HAIGH 2,536,741

DEFROSTING TIMER Filed Oct. 15, 1949 A TTWRNEYS Patented Jan. 2, 1951UNITED-- PATENT OFF ICE.

DEFROSTING' TIMERv Richard-A. Haigh; Brighton, Mich., assignor to-Automatic; Controls Gorporation, Ann Arbor, Michv, .a' corp oration-ofMichigan Application ct'ober15, 1949; SerialNo. 121,619

I Claims; 1

This invention relates to improvements in defrosting timers; thatis tosay clock controlled mitting the adjustmentof the twenty-four hour wheelof the unit to the time of day when the unit is installed independentlyof the angular position of the clOckshaft;

Still another objectis the provision of means accessible from theexterior of" the: unit casing for varying the length of the periodduringwhich defrosting takes place.

Other objects and features of novelty will appear'asI proceed with thedescription of that embodiment of the invention-which, for the pur posesof the present application, I have illustrated in the accompanyingdrawing; in which Fig. 1 is a plan view of the unit looking toward thecover of inverted cup shape, it being understood that the face of thecover stands ina: vertical plane when the unit is attached to awallreceptacle.

Fig. 2 is a plan view partially insectiorlalong theline 2--2'of Fig.3;

Fig; 3 is a View of the unit'partiallydn eleva tion and partially insection along. theli'ne33 of Fig. 1. v Fig. 4. is a large scalefragmental' viewwith the cover removed and illustrating" the Geneva.motion driving means from. the clock shaft to the twenty-four hour:wheel; a

Fig. 5 is: a, similar view. with the partsv in. the open switch ordefrosting position.

Fig. 6 is a. detail view illustrating thezmeans for disconnecting theGeneva motion. drive-when the twenty-four. hour wheel: is being:advanced.- manually in the operation of. setting" the unit in:

accordance with: the. time of day.

Fig- 7 is a detail sectional view' taken sub stantially on the line 1-1of Fig- 2;.

Fig. 8 is a large scale detail sectional view of the twenty-four hourwheelv and; associated parts.

Fig. 9 is an inverted plan view'of the rotating handle-pointedcorresponding to thehour hand of a twenty-four hour clock,.and;

Fig. 10 is an: inverted plan view of the: arm. whichv moves with thepointed and; adjustable relatively thereto for. varying the defrostingperiod.

The defrostingsunit-of the present; invention; comprises a flatbase i5.upon: which theworking;

parts of the. unit. are mounted and a cover; lzfi.

shaped like an: inverted. cup and secured. to. the:

base by means of a plurality of screws i! which extend through openingsin the base and are threaded into holes l8- formed in bosses project inginwardly from the cover walls. The two casing parts arepreferabiyconstructed of molded plastic.

A pair of metal prongs l9 extend through the base IS-near the perimeterthereof, being preferably fixed in the base during the molding opera-'-tion. These prongs have lateral oiiset portions which engage a smallledge 2| on the base. From the upper ends-of the oiTset portions fingers22-" project inwardly and are electrically connected tothe-ends of thecoil 23 of asynchronous motor. The coil is wound upon a laminated core2d which is securedto the base [5 by bolts or screws, thus holding thecoil 23-firmly'in place.

One of the cover bosses is provided with a pair of slots 25: which.snugly receive the offsets 23' of the prongs when the cover is mountedin place. These. slots-may be tapered with the point of? the: taperuppermost so that the offsets are readily received within the slots whenthe cover islputinplace; Because of this construction the prongs have a.firm bearing notonly in the base is but: alsoin the cover portion of thecasing at av point. spaced. from the first named bearing. Hencethe-mechanical connection of the. prongstothe casing isv especiallystrong and rigid, which is an. important. consideration. since. the.prongs, in addition tomaking the necessary electrical connection of theunit with: thehouse wires, serve as: the support: for the. unit. Whenthe unit is. in. use. the prongs extend into a. wall socket. or.receptacle, bringing the base l5 into a vertical plane against, thereceptacle or wall.

The. internal construction. of the unit comprises bracket. means forsupporting the various working parts. As'illustrated herein thisbracketmeans, which is omitted from Figs. 4 and 5 for. the: sake of clearness,includes an inverted sheet metal U- member 2'1. with an. extension 23.to which. is: attached av socket 2-3, that projects through a slot. 38in the cover Hi. and is intended toreceive the'plug: on; the electricconductor for the refrigeraton. Bracket member 2'1 supports theupper'bearingsl. for theshaft 32. of the clock 33. Bracket; member 27also has a pair of arms. and 35: which support a strip. of insulatingmaterial 36 upon. which are carried. the switch anditsaact'uating leverpresently to be described.

Thev bracket memberv 2?; has attached thereto a: second: upwardlyextending inverted U member 31: of: sheet metal, the function of whichis I to support the-upper bearing 38 for the twentyfour hour wheel 39.This wheel has a downwardly projecting shaft ii which is journaled inthe bracket member 21.

Wheel 39 is driven from shaft 32 by a Geneva motion drive of novel form.Wheel 38: is provided with twenty-four peripheral notches 4|, providingtwenty-four teeth 42. Surrounding shaft 32 there is a spiral spring 43of several convolutions which normally grips the shaft closely. At itsupper end it has a tangentially projecting part 44 and a downwardlyextending,

offset arm 45 which is adapted to extend into the notches 4| of thewheel. Shaft 32 makes one revolution per hour in the counterclockwisedirection as viewed in Figs. 4, and 6, and once for each revolution theoffset arm 45 enters one of the notches 4| and advances wheel 39onetwenty-fourth of a revolution clockwise. 46 is a spring detentadapted to engage a notch of the wheel, this detent yielding as theoffset arm 45 turns wheel 39, traveling over a tooth 42 and snappinginto the next notch 4| of the wheel. Detent 46 therefore holds the wheelagainst accidental movement and insures its advancement the properdistance as the offset arm 45 of the spring leaves the recess with whichit has been in engagement.

The shaft for wheel 39 has a large diameter portion 40 above the Wheelin which there is a diametrical slot 41 for a purpose which willpresently appear. Surrounding this shaft 40' there is a sleeve 48 whichextends down into a cavity 49 in the wheel. Sleeve 48 has a right angleextension 50 also disposed in cavity 49. At the outer end of thisextension there is a downwardly extending pin 5| which projects througha slot 52 in the wheel. A second pin 53 integral with wheel 39 projectsdownwardly therefrom, these two pins 5| and 53 being disposed atapproximately the same radial distance from the axis of the wheel.Sleeve 48 has a pair of oppositely disposed slots 54 extendingdownwardly from its upper edge. The turning of sleeve 48 through a smallangle from the position of Fig. 4 to that of Fig. 5 spaces the pins 5|and 53 further apart. Pin 5| is yieldably held in one or the other ofits two operative positions by a small hump 55 at the mid-point of theslot, there being sufficient play in the mounting of the sleeve topermit the pin to ride over this hump when the extension 50 is swungfrom one position to the other.

Referring now to the switch construction illustrated herein, theinsulation strip 38 is formed of stiff material so as to afford a rigidmounting for the switch parts. It supports two electric terminals 51 and58 having electrical connections 59 and 60. Terminal 52 is permanentlyconnected with a metallic angle post 6| which has a slot therethrough toreceive the long arm of a bell crank lever 62 and form a pivot therefor.When the switch is closed this arm occupies the position illustrated inFig. 4, in which the extremity of the short arm of the lever bearsagainst the strip 36. A fiat spring metal link 63 has a slot part way ofits length which straddles post 6| and the short arm of lever 62. Theend of link 63 beyond the slot bears against an indentation in the shortarm of the lever. At its opposite end this link carries a contact button64 and one extremity of a bowed spring 65, the other extremity of whichrests in a notch 56 in the post 6 Spring 65 therefore functions tomaintain the pivotal connection between conductor 63 and lever 62 bypushing the right hand end of the conductor toward the right as viewedin Figs. 4 and 5, and acts as an electrical conductor between button 64and post 6|.

As the pin 5| in turning step by step clockwise strikes the long arm oflever 62 and wipes against it the lever is shifted from its Fig. 4position to that of Fig. 5, which pulls downward flat link 63 below thenotch 66. This snaps the link 63 over dead center and causes the contactbutton 64 to snap down against a stop 61 carried by insulation strip 36,thereby opening the circuit. Before pin 5| passes beyond the end oflever 62, pin 53 comes into contact with the lever and holds it up. Whenthe pins are spaced as in Fig. 5 the period of their contact with thelever is of course longer than when the pins are close together as inFig. 4. When pin 53 moves out of contact with lever 62 the spring bypulling upon the short arm of the lever swings the latter to the Fig. 4position, causing the link 63 to shift over to a position above thenotch 66 which snaps the contact 64 upwardly into engagement with theterminal 58, again closing the switch.

While I have described more or less in detail a particular type ofswitch that is suitable for the purposes of the invention, it will beunderstood that any other switch capable of being actuated by a leversimilar to lever 62 may be employed.

When the casing parts l5 and I6 are assembled the shaft 40 and sleeve 48project through a hole 69 in the casing cover I6. An adjusting arm 70shown inverted in Fig. 10 is then slipped over the sleeve 48. It isprovided with two splines H which enter the slots 54 in the sleeve,thereby locking these two members together against relative rotation. Atthe outer extremity of arm Ill there is a pin 12 which projectsupwardly. When the adjusting arm 10 is in place a handle-pointer 13 isslipped down over the upper extremity of shaft 40', arcuate shaped walls14 on the handle receiving the shaft and a transverse rib 15 enteringthe slot 41 at the end of the shaft, thereby locking the pointer to theshaft.

. At its rear end the pointer 13 has an arcuate cutout l6 which receivesthe pin 12 on the arm 10. At the ends of this cutout the handle-pointerbears indicia indicating the adjustment for the period of defrosting. Inthis case the indicia are the numbers 3 and 4 indicating defrostingperiods 'of three and four hours respectively. In the nor- .maloperation of the device the handle-pointer l3 and the arm 10 movetogether step by step. On the face of the cover there are printednumbers indicating the time of day in one hour steps both a. m. and p.m.

When one of these units is to be installed the operator turns thehandle-pointer l3 clockwise to the time indicated on the face of thecover which is nearest to the then time of day. If at the time this isdone the offset arm 45 of spring 43 happens to be out of contact withthe wheel 39, as for example in Fig. 5, the rotation of the handlemerely causes the spring detent 45 to click from one notch to the nextas the wheel is turned. If on the other hand the arm 45 of the springhappens to be in engagement with the wheel, as in Fig. 4, it tends tooppose rotation of the wheel. A slight additional pressure on the wheelby the operator however then unwinds spring 43 slightly, therebyloosening the grip of the spring upon shaft 32 as indicated in Fig. 6 ofthe drawing. After the grip is thus loosened the spring is read.- ilyturned bodily on the shaft 32 without placing any undue strain on theshaft or the clock mech anism connected thereto. It will be observedtherefore that when the clock shaft is the driving member the springtends to wind itself tightly upon the shaft, whereas when the wheel 39is the driving member, as in setting the handlepointer to the time ofday, the spring unwinds and loosens its grip upon the shaft.

Respecting the electric circuits it will" be ob vious that currententers the unit through:v one of the prongs 1-9- and, flows to one ofthe-connections in the socket 29, asby the: conductor 80, thence throughtherefrigerator cord to the refri'gerator motor, backto'theother-'connecti'on in socket 2 9, through a conductor 81 to switchconmotion 59, through the switch to connection 60 and thence by a conductor82 to the other prong IS. The coil 23 of the clock takes its currentdirectly from the prongs l9, as previously described.

The operation of the device it is believed will be clear from theforegoing description of its construction. The pins 51 and 53 are sodisposed with respect to the handle-pointer 13 that during the earlymorning hours following midnight the switch will be opened for three orfour hours, as may be desired, to accomplish the defrosting operation,thereby freeing the refrigerator coils of frost and ice insulation onceevery twenty-four hours and enabling the refrigerator to operate atmaximum efficiency.

It will be apparent that the unit is compact and sturdy, economical tomanufacture and assemble, simple to install and not likely to get out oforder. The provisions for adjusting it to the time of day and forvarying the length of the defrosting period are particularly noteworthyand important.

Having thus described my invention, I claim:

1. In an electrical timing unit, a clock having an hour shaft rotatingin a given direction, a second shaft parallel to said clock shaft, awheel on said second shaft having peripheral notches therein, yieldablemeans carried by said clock shaft and projecting laterally therefrom formeshing engagement with said notches one at a time and adapted to impartintermittent rotation to said wheel in the reverse direction, a switch,means for actuating said switch comprising a projection turning withsaid wheel, and means for manually turning said wheel in said reversedirection, said yieldable means being adapted to yield and permit saidmanual turning in said reverse direction, whereby the angular positionof said wheel relative to that of said clock shaft may be manuallyselected.

2. In an electrical timing unit, a clock having an hour shaft rotatingin a given direction, a second shaft parallel to said clock shaft, awheel on said second shaft having peripheral notches therein, meanscarried by said clock shaft projecting laterally therefrom forintermittent meshing engagement with said notches one at a time andadapted to impart positive step by step rotation to said wheel in thereverse direction, and means for manually turning said wheel in saidreverse direction, said first named means being adapted to yield forpermitting rotation of said wheel in said reverse directon, whereby theangular position of said wheel relative to that of said clock shaft maybe manually selected.

3. In an electrical timing unit, a clock having a rotating hour shaft, asecond shaft parallel to said clock shaft, a wheel on said second shafthaving peripheral notches therein, a coil spring surrounding andgripping said clock shaft, one end of said coil spring having an offsetarm adapted to enter said notches one after another for impartingintermittent motion to said wheel, a switch adapted to be actuated bysaid wheel as it moves through a predetermined arc, and manual means forturning said wheel in a direction for causing a notch to bear againstsaid offset arm, unwind said spring, thereby loosening its grip uponsaid shaft and turning the spring bodily, onisaid shaft, whereby the.angular position of the wheel may be changed while that of the clockshaft remains unaffected.

4. In an" electric timing unit; a clock having an hour. shaft rotatablein" given directiorn a;

secondlshaf-t parallel to saidclock shaft, a: wheel on said second shafthaving peripheral notches therein, a coil spring surroundin said clockshaft, one end of said coil spring having an onset arm adapted to entersaid notches one after another for imparting intermittent motion to saidwheel, the rotation of said clock shaft acting when said arm is inengagement with a notch in said wheel to wind the spring tightly on saidshaft for imparting a positive rotational movement to said wheel in adirection reverse to that of said clock shaft, a switch adapted to beactuated by said wheel as it moves through a predetermined arc in saidreverse direction, and manual means for turning said wheel in saidreverse direction, thereby causing a notch of the wheel to bear againstsaid offset arm, unwind said spring, thereby loosening its grip uponsaid shaft and turning the spring bodily on said shaft, whereby theangular position of the wheel may be changed while that of the clockshaft remains unaffected.

5. In an electric timing unit, a rotatable wheel, means for impartingintermittent rotation to said wheel, an electric switch, a movableelement for actuating said switch, said element being biased towardswitch closing position a pair of pins movable with said wheel adaptedto engage and shift said movable element once during each revolution ofthe wheel to open said switch and maintain it open through a given angleof rotation of the wheel, and manual means for moving one of said pinsin an arcuate path through a small angle to adjust the spacing of thepins and thereby vary the length of time during which said movableelement is maintained in switch opening position.

6. An electric timing unit as defined in claim 5 comprising a sleevesurrounding said second shaft and rotatable thereon through a limitedarc, said movable pin being carried by said sleeve, and an arm mountedon said sleeve manually adjustable through said limited arc.

7. In an electric timing unit, a casing, a clock having a rotating hourshaft, a second shaft parallel to said clock shaft projecting throughsaid casing, a wheel keyed to said second shaft within the casing,Geneva motion means for imparting intermittent rotation to said wheelfrom said clock shaft, an electric switch, a movable element foractuating said switch, a sleeve surrounding said second shaft, a pincarried by said wheel and a pin carried by said sleeve at the sameradial distance from said second shaft, said pins being adapted jointlyto engage and operate said movable element once during each revolutionof the wheel, a handle outside the casing keyed to said shaft, an armoutside the casing keyed to said sleeve and arranged for adjustmentthrough a limited are relative to said handle, and means on the handleholding said arm in adjusted position, whereby the pin on said sleevemay be adjusted relative to the pin on said wheel for regulating thelength of time of actuation of said movable element and the consequentactuation of said switch.

RICHARD A. HAIGH.

(References on following page) REFERENCES CITED Number Name Date JohnsonDec. 24, 1935 Number 8 Name Date Sprenger et a1 Apr. 27, 1937 MinneciOct. 1, 1940 Knight Jan. 28, 1941 Jones May 4, 1943 4 Straitz June 18,1946 Avery June 28, 1949

